Medical practitioners, such as military medics, civilian emergency-medical personnel, nurses, and physicians, routinely perform vascular-access procedures (e.g., intravenous insertion, central venous line placement and peripherally-inserted central catheter, etc). It is desirable for a practitioner to be proficient at performing these procedures since the proficient practitioner is less likely to injure a patient and is almost certain to reduce the patient's level of discomfort.
Becoming proficient in vascular-access procedures requires practice. In fact, the certification and re-certification requirements of some states mandate a minimal number of needle sticks, etc., per year per provider. Historically, medical practitioners practiced needle-based procedures on live volunteers. More recently, simulation techniques and devices have been developed to provide training in vascular-access procedures without the use of live volunteers.
Some vascular-access simulation systems that are in the prior art include an interface device and a data processing system. To practice a vascular-access procedure, a user manipulates an “instrument,” which extends from the device and serves as a catheter-needle. Potentiometers and encoders within the interface device track the motion and position of the instrument and relay this information to the data processing system. The data processing system performs a simulation of the surface and subsurface anatomy of human skin, and determines the effect of the instrument's motion on the skin's anatomy. Simulated results are displayed by the data processing system. Using the motion information from the interface device, the data processing system also generates a control signal that controls a force-feedback system that is coupled to the instrument. The force-feedback system generates various resistive or reactive forces that are intended to simulate the forces that are experienced by a medical practitioner during an actual vascular-access procedure. The user senses these forces during manipulation of the instrument.
Although some systems in the prior art have the ability to simulate forces that the user feels during the manipulation of the instrument, those forces experienced by the user are often unrealistic. This is particularly the case as the instrument progresses along its intended path. There is an expectation that the forces experienced using the instrument should change in a realistic way as a function of (i) the insertion displacement and (ii) the point of insertion on the anatomy.
The inability of prior-art vascular-access simulation systems to realistically simulate a vascular-access procedure limits their usefulness as training or accreditation tools.